The Utility of Trendlines
Case: #15 Triple Fan Trendline
There is an origin point and three successive points on a Triple Fan trendline. The trendline from the origin to the first extreme, the second extreme, and finally the third extreme.
In a triple fan, a price break to the third extreme trendline typically signals a significant price move.
Have a look at real world example of Triple Fan Trendline
Let's take a look at Tesla on 13 Jul '21, a 1 hr chart. The break of the third trendline signals a significant price move, which is exactly what happen in Tesla. It all began with that break of that final 3rd trendline.
When the highs and lows of a price bar form above or below a trendline, it is considered a significant trendline break.